The interaction model of World Wide Web WWW is based on a simple client-server interaction as shown in FIG. 1. The client-server relationship can be defined by the relationship between functional entities (for example, managed objects or network layers) in which one entity uses a service provided by another. The user of the service may be called a “client” and the provider of the service may be called a “server”. The term interaction can be described as a situation that occurs when one service affects the operation of the other service.
The basis of WWW interaction is that the client requests a resource from the server based on a uniform resource identifier (URI), e.g. uniform resource locator (URL). This identifier individualizes both a file or a directory in the Internet and a protocol needed to use them. Based on this interaction model the server is able to provide some service to the client.
In the process of this interaction the server will often require data from the client. Such data may include the client's PKI (Public Key Infrastructure) Digital Certificate, or perhaps some details about the user on whose behalf the client makes the requests (e.g. username, password, users address).
Due to various constraints in the wireless world the interaction model differs from the model described above. In the wireless model an additional server is introduced to distribute the load across the network. This interaction model is shown in FIG. 2. Instead of making the request of the client directly via the link A, the origin server can request information about the client off the supporting server via the link B.
These supporting servers have many uses. Some examples are:                gathering location data about the user (Location Servers);        storing and distributing of identity certificates on behalf of the user (Certificate Servers);        describing the attributes of a user's terminal (User Agent Profile Server); and        acting as repositories of data.        
For various reasons (including legislative) it is considered that personal data should be distributed within strict guidelines. In recent years there has been growing concern about users' privacy on the Internet. This has lead to various guidelines and directives from organizations like OECD (Organization for Economic Co-operation and development) and EU (European Union). The guidelines although quite similar from the various sources are well summed up by the US FTC (United States Federal Trade Commission) Fair Information Practices (FIP) in the Electronic Marketplace. The FIP recommends that users' privacy should follow the 4 following guidelines (http://www.ftc.gov/privacy/index.html):                Notice—A user should be notified what personal data is used, who is using it, and how it is used;        Choice—A user should have a choice as to whether or not to allow that use;        Access—A User should have access to that data where ever it is used; and        Security—User data should be protected at all times using reasonable security precautions.        
The World-Wide-Web Consortium (W3C) has defined a mechanism for terminals to determine the conditions under which personal information may be transmitted to applications. The mechanism is called P3P (Patform for Privacy Preferences. It is actually a framework for:                defining privacy policy on application servers (i.e. specifying formally what information is gathered and how it is used);        defining how clients may define their own privacy preferences; and        how privacy policies may be compared.        
P3P does not prescribe specific implementations (beyond relying upon XML (Extensible Markup Language) for defining the policies), but several prototype systems provide the following functions:                alerting the user each time a WWW site is accessed whose policy differs from the user preferences; and        requesting the user to authorize the transmission of personal information to the WWW-site.        
There exist two state of the art methods for accessing control to user data. A very common access control method is that of using black/white list to control the access to a resource. A black list is a list of entities not allowed to access the resource. If the black list exists all entities are allowed to access the list except those on the black list. A white list is the list of entities allowed to access the resource. If the white list exists no entities are allowed to access the list except those on the white list.
Although this is a rather simple way to provide the level of privacy protection there are some drawbacks, reasons why the method is not applicable to support privacy invoking within guidelines. It is a static method and it has no way of dynamically dealing with data requests. Supposing the user wishes to visit the origin server. The steps they would have to go through are as follows:
1) First they would have to determine what data the origin server may require;
2) Then they would have to go to the appropriate supporting server (or servers as there may be several involved);
3) Then they can proceed to the origin server in order to be served.
Furthermore, there is only the possibility of black or white lists. There is no capability of having a “grey” list where the user is queried to see if they wish to allow the origin server have the data.
Another possibility for accessing control is a method in which the origin server assembles a set of the data it requires and presents it as a list for the client to digitally sign. The origin server then presents this digitally signed list to the supporting server when requesting the personal user data. This method would however involve extra round trips and cryptographic processing on the client. It was precisely these problems that required the use of supporting servers. In other words this scheme would negate the advantage of supporting servers.
The scheme relies on PKI which in turn requires digital certificates. As the digital certificate itself can contain personal user data the simple fact of using the digital certificate could in itself compromise user privacy.
Partially due to the fact that “Privacy” as such is a new area there has been no efforts made in the standards which refer to supporting servers to address the privacy issue. It can clearly be seen from the above use cases that the data contained on supporting servers is personal user data, and that data should be used in accordance with the appropriate privacy guidelines.
One of the problems associated with the above mentioned current situation is that privacy has not been addressed in wireless Internet standards. Thus there is no defined nor implemented method for supporting servers to protect the privacy wishes of users. Currently the situation with supporting servers is that there is no intervention on behalf of the user when the supporting server receives the request for information. This means that there is no way for the user to receive notice or make a choice with regards to her/his own personal data.